Occurrence and distribution of microbial pollutants in coastal areas of the Adriatic Sea influenced by river discharge. (15th September 2021)

• Record Type: Journal Article
• Authors: Basili, Marco; Campanelli, Alessandra; Frapiccini, Emanuela; Luna, Gian Marco; Quero, Grazia Marina
• Is Part Of: Environmental pollution. Volume 285(2021)
• Publication Date: 2021-09-15
• Subjects: Microbial pollution -- Coastal rivers -- Adriatic sea -- Metabarcoding -- Source tracking; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2021.117672
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: The transport of a variety of pollutants from agricultural, industrial and urbanised areas makes rivers major contributors to the contamination of coastal marine environments. Too little is known of their role in carrying pathogens to the coast. We used DNA-based metabarcoding data to describe the microbial community composition in seawater and sediment collected in front of the estuary of the Tronto, the Chienti and the Esino, three Italian rivers with different pollution levels that empty into the north-central Adriatic Sea, and to detect and measure within these communities the relative abundance of microbial pollutants, including traditional faecal indicators and alternative faecal and sewage-associated pollutants. We then applied the FORENSIC algorithm to distinguish human from non-human sources of microbial pollution and FAPROTAX to map prokaryotic clades to established metabolic or other ecologically relevant functions. Finally, we searched the dataset for other common pathogenic taxa. Seawater and sediment contained numerous potentially pathogenic bacteria, mainly faecal and sewage-associated. The samples collected in front of the Tronto estuary showed the highest level of contamination, likely sewage-associated. The pathogenic signature showed a weak but positive correlation with some nutrients and strong correlations with some polycyclic aromatic hydrocarbons. This study confirms that rivers transport pathogenic bacteria to the coastal sea and highlights the value of expanding the use of HTS data, source tracking and functional identification tools to detect microbial pollutants and identify their sources with a view to gaining a better understanding of the pathways of sewage-associated discharges to the sea. Graphical abstract: Image 1 Highlights: Rivers can be major contributors to the pollution of coastal marine environments. The role of rivers in transporting pathogens to the coast still remain unanswered. Traditional, alternative and sewage-related faecal pollutants were found. Both seawater and sediment were presumptively contaminated by potential pathogens. Correlations between pathogenic signature and anthropogenic impact were found. Abstract : Faecal and sewage-associated bacteria released by coastal rivers make these waterways a source of potentially pathogenic bacteria in the coastal sea.